Quick-change drill chuck

A drill comprising:

• a drive spindle centered on and rotatable about a spindle axis and formed centered on the axis with an axially forwardly open socket of noncircular section and with at least one radially throughgoing passage open radially inward into the socket;
• a chuck body;
• a stem of noncircular section complementary to that of the socket, fixed to the chuck body, and extending along a stem axis from the chuck body, the stem being formed with a radially outwardly open recess;
• a locking element radially displaceable in the passage between an inner position projecting radially inward into the socket and an outer position clear of the socket and projecting radially outward from the spindle, the stem being fittable to the socket with its recess aligned with the passage;
• and
• a collar formed with an inner surface closely juxtaposed with an outside surface of the spindle and with a radially inwardly open recess, the collar being axially displaceable on the spindle between a locked position with its inner surface pressing the element into the inner position and an unlocked position with its recess level with the element and the element movable into the outer position engaged in the collar recess.